How many times is a proton heavier than an electron?

Given two atoms: Atom A has 17 protons, 18 neutrons, and 17 electrons. Atom B has 18 protons, 18 neutrons, and 18 electrons. Which statement is correct?

An element has a full outermost electron shell. What can be inferred about its chemical reactivity?

Describe the main limitation of the Bohr model of the atom.

An element 'X' has 12 electrons. Which of the following elements would it likely form a stable compound with?

Which experiment demonstrated that atoms contain negatively charged particles called electrons?

Explain how the existence of isotopes contradicts one of the main postulates of Dalton's atomic theory.

Consider a neutral atom with an atomic number of 20. If it forms an ion, what would be the most likely charge on this ion?

Which of the following statements about the arrangement of electrons in shells is consistent with the Bohr-Bury rules?

Why are some atoms of the same element found to have different mass numbers?

An element has an electronic configuration of 2, 8, 8, 1. What is its valency, and what type of ion would it form?

Explain the concept of an electron shell or energy level in the context of atomic structure.

Which of the following subatomic particles has a mass approximately equal to that of a proton but carries no electrical charge?

An ion of element Z has a mass number of 32, 16 protons, and a charge of -2. How many neutrons and electrons does this ion have?

Why was the 'plum pudding' model unable to explain the results of the alpha-particle scattering experiment?

An atom X has an atomic number of 9 and an atom Y has an atomic number of 11. Describe the type of bond they would most likely form with each other.

What is the maximum number of electrons that can be held in the outermost shell of an atom, according to the Bohr-Bury scheme, and what is this rule called?

If an atom has 19 electrons, 19 protons, and 20 neutrons, what is its symbol with mass number and atomic number?

An element P has 11 electrons and belongs to the 3rd period. What is its valency, and what type of compound would it most likely form with oxygen?

Which of the following correctly describes the particles found in the nucleus of an atom?

Explain how the concept of valency helps in writing the chemical formula of ionic compounds.

Consider a hypothetical atom with 12 protons and 12 neutrons. If this atom undergoes a chemical reaction where it becomes an ion with a -2 charge, how many electrons does this ion possess?

Why is the Bohr model still used as a simplified representation for teaching atomic structure, despite its limitations?

An element has 5 electrons in its outermost shell and belongs to the 3rd period. What is its atomic number?

What was the significance of the "empty space" concept in Rutherford's model of the atom, compared to Thomson's model?

An element has 13 protons, 14 neutrons, and 10 electrons. What is its atomic number, mass number, and net charge?

Why are electrons considered to have negligible mass compared to protons and neutrons, even though they are fundamental particles?

If an element forms an ion with a charge of +2 and has 18 electrons, what is its atomic number?

What is the maximum number of electrons that can be accommodated in the N-shell (fourth shell) of an atom?

Describe the main difference in how electrons are depicted in Rutherford's model versus Bohr's model.

If a neutral atom has 15 protons and its mass number is 31, how many energy shells are occupied by electrons, and how many electrons are in the outermost shell?

Which of the following pairs are isotopes?

What role do neutrons play in the stability of atomic nuclei, particularly for heavier elements?

An element has an atomic number of 16. What will be its electronic configuration, valency, and type of ion formed?

Explain the primary difference between the atomic number (Z) and the mass number (A) of an atom.

An atom of element Y has 17 protons and 20 neutrons. What is its mass number and atomic number?

How do you determine the group and period of an element based on its electronic configuration, assuming it's a main group element?

If an atom of an element has 19 electrons, what is the maximum number of electrons that can be accommodated in its third shell (M-shell)?

An atom has an electron configuration of 2, 8, 8. What is its atomic number, and is it likely to be reactive or unreactive?

Which of the following statements about the Bohr model of the atom is incorrect?

Describe the main difference between a cation and an anion, including how each is formed.

Consider an element X that forms an oxide with the formula X2O3. What is the probable electronic configuration of X if it is in the third period?

Why is the atomic number a more fundamental property for defining an element than the mass number?

Given a sample of natural neon, which consists of three isotopes: Ne-20 (90.92%), Ne-21 (0.26%), and Ne-22 (8.82%). Explain why the atomic mass of neon is approximately 20.18 amu, and not a whole number.

An element has electronic configuration 2, 8, 4. What is its group number and period number in the periodic table?

Why are canal rays deflected towards the negative plate in an electric field?

An ion has 18 electrons and 17 protons. What is its symbol and charge?

Contrast the main features of Thomson's atomic model with Rutherford's atomic model.

An atom has an atomic number 17 and a mass number 35. It forms a compound with hydrogen, with the formula HX. What is the valency of X in this compound?

How did the limitations of Rutherford's model regarding atomic stability pave the way for Bohr's postulations about electron orbits?

Explain the concept of valency in terms of an atom's electron configuration.

Calculate the number of protons, neutrons, and electrons in an iodide ion (I-) with a mass number of 127. The atomic number of iodine (I) is 53.

Which of the following elements would be expected to be chemically unreactive?

What experimental evidence led to the conclusion that the nucleus of an atom is positively charged?

An element has 2 valence electrons and belongs to the 4th period. Write its full electronic configuration.

Why did Rutherford's model propose that the nucleus is very small and dense compared to the overall size of the atom?

Describe one major point of agreement and one major point of disagreement between Dalton's atomic theory and modern atomic theory.

An atom has 10 protons, 10 neutrons, and 10 electrons. If it loses 2 electrons, what will be its net charge, atomic number, and mass number?

Which subatomic particle was discovered by J.J. Thomson?

Consider the elements Magnesium (Mg, Z=12) and Calcium (Ca, Z=20). Both are in Group 2 of the periodic table. How do their electron configurations explain their similar chemical properties?

Explain why the first shell (K-shell) can hold a maximum of 2 electrons, while the second shell (L-shell) can hold up to 8 electrons, according to the Bohr-Bury rules.

Which experiment provided the first evidence for the existence of a positively charged nucleus within an atom?

If an element has an atomic number Z and mass number A, how would you determine the number of protons, electrons, and neutrons in a neutral atom of this element?

An element has an atomic number 13. How many electrons are present in its M-shell (third shell) and what is its valency?

Why are atoms generally considered to be electrically neutral, despite containing charged subatomic particles?

Which of the following describes the key difference between isotopes and isobars?

What was the primary limitation of Thomson's 'plum pudding' model regarding the distribution of positive charge within the atom?

An element M forms a chloride with the formula MCl2. What is the valency of element M, and what type of ion would it typically form?

Explain why cathode rays are deflected towards the positive plate in an electric field.

Two elements, A and B, have mass numbers 40 and 39 respectively. Element A has 20 protons, while element B has 19 protons. What is the relationship between elements A and B?

Explain why the atomic mass of most elements is not a whole number.

If an atom has 15 protons and a mass number of 31, how many electrons and neutrons does a neutral atom of this element possess?

A neutral atom of an element has an electronic configuration of 2, 8, 7. What is its valency and what type of ion is it likely to form?

Describe the key limitation of Rutherford's atomic model that led to the development of Bohr's model.

An element has an atomic number of 11. Which of the following is true regarding its ion formation and reactivity?

Which of the following statements about J.J. Thomson's model of the atom is incorrect?

Why was the discovery of the neutron by James Chadwick crucial for developing a more complete model of the atom, even after protons and electrons were identified?

Consider two isotopes of carbon: Carbon-12 and Carbon-14. How do these two isotopes differ in terms of subatomic particles, and what is the implication of this difference for their chemical properties?

An element X has a valency of 3. What would be the most probable electronic configuration for an atom of this element if it is in the third period?

Rutherford's alpha-particle scattering experiment led to the rejection of Thomson's model. Explain two significant observations from Rutherford's experiment that contradicted Thomson's 'plum pudding' model.

Consider an atom with 17 protons, 18 neutrons, and 17 electrons. Which of the following statements accurately describes its atomic characteristics?

Write the complete symbol for the atom with the given atomic number [Z] & mass number [A].

How are the isotopes of hydrogen represented?

An atom contains 3 protons, 3 electrons and 4 neutrons. What is its atomic number, mass number & valency?

Why does Helium have zero valency?

From the symbol ³²₁₆S, state: i) Atomic number of sulphur ii) Mass number of sulphur iii) Electronic configuration of sulphur

Give the symbol, relative charge & mass of the three subatomic particles.

State the maximum capacity of various shells to accommodate electrons.

How many electrons are present in the valence shell of nitrogen & argon?

Which kind of elements have tendency to lose electrons? Give example.

What are valence electrons? Give example.

Give one achievement and one limitation of J.J. Thomson's model of atom.

Identify the isotopes out of A, B, C & D: ³³A₁₇, ⁴⁰B₂₀, ³⁷C₁₇, ³⁹D₁₉

Write the charges on subatomic particles.

Define the following terms: a) Atomic number b) Mass number

Name the particles which determine the mass of an atom.

What are isobars?

Give the number of protons in ³⁵Cl₁₇.

What type of charge is present on the nucleus of an atom?

How many electrons at the maximum can be present in the first shell?

What was the model of an atom proposed by Thomson?

Which is heavier, neutron or proton?

Name the scientist and his experiment which proved that the nucleus of an atom is positively charged.